Machine for bending a profile in two bending directions and bending tool

ABSTRACT

The invention relates to a machine for bending a profile in two bending directions, that comprises a bending tool including at least two clamping forms ( 19 ) centred on the profile bending axis and having the shape of disks having planar junction surfaces ( 19   a ) extending in planes perpendicular to said bending axis, in which are formed two rectilinear grooves ( 20   b,    21   b ) and a peripheral rebate ( 22   b ) extending between said grooves and profiled as a continuation thereof, the grooves and the rebate being adapted so that, in the joined position of the junction surfaces ( 19   a ) of two clamping foams, the joined grooves define two clamping ducts of a profile and the joined rebates define a profile-winding bearing surface extending between said clamping ducts.

The invention concerns a machine for bending a profile in two bendingdirections and is also directed to a bending tool for such a bendingmachine.

At present standard bending machines comprise means for holding profilesand moving them along a longitudinal axis (x) and a bending headrotatable about a bending axis (z), said bending head including asstandard a bending roller and a clamping jaw having bearing surfacesbetween which a profile to be bent passes, is clamped and then bent:

the bending roller axis coinciding with the bending axis (z), andthe clamping jaw being mobile in translation relative to the bendingroller along an axis perpendicular to the bending axis (z) between aposition joined with said bending roller for clamping and bending aprofile to be bent and a position spaced from said bending roller forintroducing a profile to be bent between the latter and said clampingjaw.

Such machines have a kinematic combining relative movement of thebending roller and the clamping jaw along an axis perpendicular to thebending axis (z) and simultaneous rotation of the bending roller and theclamping jaw about the bending axis (z) in the position in which theyare joined.

One particular advantage of such a kinematic is to enable the design ofmachines for bending profiles in two bending directions and many bendingmachines of this type exist at present.

On the other hand, this kinematic leads to the production of relativelycomplex bending heads that furthermore have a relatively large overallsize.

Moreover, an additional disadvantage of such bending machines is thatthe bending angle is limited to 180°, or less than 180° if the end ofthe bent length carries an item such as a nut to enable disengagement ofthe profile after bending.

One solution to alleviating these drawbacks has been to design bendingmachines such as are described in particular in the patent applicationsFR2117745, EP1561522 and EP0737526 having a totally different kinematicand the bending head of which comprises:

at least two clamping forms whose axis is the bending axis (z), takingthe form of discs having plane junction faces extending in planesperpendicular to said bending axis, in which are formed a rectilineargroove with a longitudinal axis perpendicular to the bending radius,having an end face for introduction of a profile (P), and a peripheralrebate profiled in continuity with the introduction face of said groove,said groove and said rebate being such that, in the joined position ofthe junction faces of two clamping forms, two joined grooves delimit aduct for bending a profile (P) having an end face for introducing saidprofile, and the joined rebates define, in continuity with saidintroduction face, a bending bearing surface for said profile,means for relative movement in translation of the clamping forms alongthe bending axis (z), adapted to move them between a spaced-apartposition for introducing and removing a profile (P) and a joinedposition for bending said profile, androtation drive means adapted to drive simultaneous rotation of theclamping forms in their joined position.

Such bending machines therefore have a kinematic combining relativemovement of the clamping forms along the bending axis (z) andsimultaneous rotation of the bending forms about that bending axis (z)in the position in which they are joined.

According to this principle, the bending head thus includes clampingforms whose axis is the bending axis (z) that are adapted to move alongthat axis and to turn about it.

This design significantly reduces the overall size of the bending headsand simplifies the design of said bending heads because of a kinematichaving a single reference axis, namely the bending axis (z).

Moreover, in the spaced-apart position of the clamping forms, the lattertotally free the plane in which the profile is situated, with the resultthat removing it does not give rise to any problem even if the bendingangle is greater than 180°.

On the other hand, the major drawback of such bending machines is thatthey enable bending in only one bending direction.

The present invention aims to alleviate this drawback and has for itsmain object the provision of a bending machine of the type describedabove, i.e. the kinematic of which has only one reference axis, adaptedto bend a profile in two bending directions.

Another object of the invention is to provide a machine for bending aprofile in two bending directions enabling bending angles greater than180° to be produced. To this end, the invention is aimed at a bendingmachine having a bending head as described in the above preamble,characterised in that:

the clamping forms include in each of their junction faces a rectilinearsecond groove following with the rectilinear first groove a pair ofgrooves delimiting in the joined position of the junction faces of thetwo clamping forms two clamping ducts between the introduction faces ofwhich extends the bending bearing surface for the profiles (P) formed bythe two peripheral rebates joined, the arrangement of said grooves andrebates being such that the bending bearing surface for the profilesdelimits between the introduction faces of the two clamping ducts acircular arc at least equal to 270° adapted to enable the bending of alength of profile (P):

either in a first bending direction using one of the two pairs ofgrooves, by rotation of the clamping forms in a first rotationdirection,

or in a second bending direction using the other pair of grooves, byrotation of the clamping forms in a rotation direction that is theopposite of the first rotation direction,

means for relative movement of the means for holding the profile (P) andthe bending head are adapted to place the axis of one or the other pairof grooves on the longitudinal axis (x).

Thus the invention consists in providing two grooves in the junctionface of each clamping form, each for bending profiles in one bendingdirection, and a rebate, arranged so that the groove not being used forbending is “retracted” relative to the longitudinal bending axis. Thissolution therefore produces machines for bending in two bendingdirections including bending heads of identical overall size and designto those of present-day bending machines the kinematic of which has onlyone reference axis.

This design further enables bending angles greater than 180° to beproduced, notably as a function of the required maximum value of thatbending angle, the pair of grooves produced in the junction face of eachclamping form is advantageously such that the rebate produced betweenthe introduction faces of said grooves delimits a circular arc between270° and 315° inclusive.

According to another advantageous embodiment of the invention aimed at abending machine comprising two rules disposed on the upstream side ofthe clamping forms and adapted to enable the bending of a profile byeach of the pairs of grooves, said rules are advantageously mounted on asingle carriage associated with means for moving said carriage.

This arrangement of the rules on a single carriage constitutes a highlyadvantageous disposition significantly simplifying the bending machine.The movement of such rules requires only one guide and only one feedcontrol system, instead of the two guides and two control systemsrequired for present-day machines enabling bending in two directions.

According to another advantageous embodiment of the invention, the meansfor driving the clamping forms in rotation include an axial openingproduced in each of said clamping forms and a rotary shaft adapted toextend in these openings, said openings and said rotary shaft havingconjugate members for immobilizing them relative to each other inrotation. Moreover, in a first advantageous variant of the inventionaimed at a bending machine comprising two clamping forms, one of saidclamping forms, referred to as the fixed form, is fixed in translationalong the bending axis (z) and the other bending form, referred to asthe mobile form, is mounted on means for moving said mobile clampingform in translation along the bending axis (z).

On the subject of this first variant, the rotary shaft is furthermoreadvantageously carried by means for moving said rotary shaft intranslation along the bending axis (z) adapted to enable it to be heldengaged with the two clamping forms in each of the relative positions ofsaid clamping forms and notably the joined and spaced apart extremepositions thereof. Moreover, in the spaced-apart position of the twoclamping forms the means for moving the rotary shaft in translationalong the bending axis (z) are advantageously adapted to enable thelatter to be placed either in a position referred to as the deployedposition in which said rotary shaft is engaged with the clamping formsor in a position called the retracted position in which said rotaryshaft frees, between the two junction faces of said clamping forms, aspace adapted to enable the passage of the profile in order to changethe bending direction.

This disposition significantly simplifies the kinematic of movement ofthe profiles on changes of bending direction, because this requires onlyone movement along an axis orthogonal to the longitudinal axis (x).

According to a second advantageous variant of the invention aimed at abending machine comprising three clamping forms, those three clampingforms advantageously consist in:

a clamping form referred to as the intermediate clamping form havingopposite upper and lower junction faces,

a clamping form referred to as the upper clamping form having a junctionface adapted to cooperate with the upper junction face of theintermediate clamping form, and

a clamping form referred to as the lower clamping form having a junctionface adapted to cooperate with the lower junction face of theintermediate clamping form,

the grooves and rebates produced in the upper clamping form and theupper junction face of the intermediate clamping form having dimensionsdifferent from those of the grooves and rebates produced in the lowerclamping form and the lower junction face of the intermediate clampingform to enable the bending of profiles with different sections.Moreover, this bending machine then further comprises means for relativemovement of the means for holding the profile and the bending headadapted to position said profile facing one or the other pair ofclamping forms.

Furthermore, in this second variant:

one of the upper and lower bending form is advantageously fixed intranslation along the bending axis (z), andthe rotary shaft is advantageously constrained to move in translationwith the other of the upper and lower clamping form and is adapted tobring the three clamping forms to their joined position against theaction of spring means disposed between the respective junction faces ofsaid clamping forms.

The invention is also directed to a tool for bending a profile about abending axis (z), comprising at least two bending forms having junctionfaces in which are formed a rectilinear groove and a peripheral rebateprofiled in continuity with said groove. According to the invention, theclamping forms of this tools include, formed in each of their junctionfaces, a rectilinear second groove foaming with the rectilinear firstgroove a pair of grooves delimiting in the joined position of thejunction faces of the two clamping forms two clamping ducts between theintroduction faces of which extends the bending bearing surface for theprofiles (P) formed of the two peripheral rebates joined, thearrangement of said grooves and rebates being such that the windingbearing surface for the profiles delimits between the introduction facesof the two clamping ducts a circular arc at least equal to 270° adaptedto allow the bending of a length of profile (P):

either in a first bending direction using one of the two pairs ofgrooves, by rotation of the clamping forms in a first direction,or in a second bending direction using the other pair of grooves, byrotation of the clamping forms in a rotation direction that is theopposite of the first rotation direction.

The invention further encompasses a tool as defined hereinabove havingseparately or in combination any of the advantageous features stated inthe text and the claims of the present application.

Other features, aims and advantages of the invention will emerge fromthe following detailed description with reference to the appendeddrawings, which represent by way of non-limiting examples two preferredembodiments of the invention and a variant of the second embodiment. Inthese drawings:

FIG. 1 is a diagrammatic perspective view of a first embodiment of abending machine of the invention including two clamping forms,

FIG. 2 is a partially cut away front view of the bending head of thisfirst embodiment in the position with the two clamping forms joined,

FIGS. 3 a and 3 b are two partial and partially cut-away front viewsrepresenting two distinct states of the bending head of this firstembodiment in the spaced-apart position of the two clamping forms,

FIG. 4 is a perspective view of a clamping form of the invention,

FIG. 5 is a diagrammatic perspective view of a second embodiment of abending machine of the invention including three bending forms,

FIG. 6 is a partially cut-away front view of the bending head of thissecond embodiment in the position with the three clamping forms joined,

FIG. 7 is a partial and partially cut-away front view representing thebending head of this second embodiment in the spaced-apart position ofthe three clamping forms,

FIG. 8 is a partially cut-away front view, showing in particular thepartially cut-away clamping forms, of the bending head of a variant ofthis second embodiment in the position with the two clamping formsjoined, and

FIGS. 9 a to 9 d are four diagrams representing two successive bendingoperations carried out using the first embodiment of the bending machineaccording to the invention.

The bending machines of the invention represented by way of example inthe figures are machines for bending in two bending directions a profileP carried by means of any type of means known in themselves,schematically represented at D, adapted to move said profile along ahorizontal axis (x).

Note that, in order to simplify the detailed description givenhereinafter, the bending machines are described in their usual positionof use in which, in particular, the bending axis (z) is a vertical axisand the displacement axis (x) is a horizontal axis. Consequently, theterms vertical, horizontal, etc. relate to such a position.

The bending machine having two clamping forms represented in FIG. 1comprises, firstly, a frame 1 including a vertical front plate 2.

This bending machine comprises a first carriage 3 adapted to slidehorizontally along a horizontal axis Y relative to the frame 1 andincluding a vertical table 4 having horizontal slides such as 5 adaptedto cooperate with horizontal rails such as 6 fainted on the front plate2 of the frame 1.

This first carriage 3 additionally includes an upper horizontal table 7on which a second carriage 8 is mounted to slide in translation on saidhorizontal axis Y and which has a horizontal plate 9 on the underside ofwhich are disposed horizontal rails such as 10 adapted to slide inslides such as 11 provided on said upper table 7 of the first carriage3.

The second carriage 8 also includes two parallel plates 12, 13 extendingvertically on the horizontal plate 9 each having toward their upper enda slide 14 that extends horizontally along an axis X perpendicular tothe axis Y and thus parallel to the axis (x) of movement of the profileP.

Each of these slides 14 is adapted to house a sliding rail 15 forsupporting a guide rule 16, 17 of standard type, i.e. including alongitudinal bearing and guide groove for the profile to be bent.

The bending machine represented in FIG. 1 further includes a bendingtool disposed in front of the second carriage 8 and adapted to cooperatewith one or the other of the guide rules 16, 17 in order to enablebending in two bending directions.

This tool consists of two clamping forms 18, 19 whose axis is a verticalbending axis (z) taking the form of discs having plane junction faces 18a, 19 a extending in horizontal planes (X, Y) perpendicular to saidbending axis and at the periphery of which are formed two rectilineargrooves with a longitudinal axis perpendicular to the bending radius,respectively grooves 20 a, 21 a for the clamping form 18 and grooves 20b, 21 b for the clamping form 19, between which extends a respectiveperipheral rebate 22 a, 22 b.

These grooves 20 a, 20 b, 21 a, 21 b and rebates 22 a, 22 b are,firstly, such that in the position with the junction faces 18 a, 19 a ofthe two clamping forms 18, 19 joined two joined grooves 20 a-20 b, 21a-21 b delimit a clamping duct for a profile P and the joined rebates 22a-22 b define a bending bearing surface for said profile.

Moreover, the arrangement of said grooves and rebate, in associationwith one or the other rule 16, 17, enables the bending of a length ofprofile P:

either in a first bending direction using one of the two pairs ofgrooves 20 a-20 b, by rotation of the clamping forms 18, 19 in a firstrotation direction,or in a second bending direction using the other pair of grooves 21 a-21b, by rotation of the clamping forms 18, 19 in a rotation direction thatis the opposite of the first rotation direction.

In the example represented, and in order to fulfil the aforementionedfunctions, the faces F20, F21 for introduction of the profiles P of thetwo grooves 20 a, 21 a or 20 b, 21 b formed on a clamping form 18 or 19(i.e. the faces of these grooves with the rebate 22 a or 22 b betweenthem), delimit between them an angle a equal to 270°, which can beincreased up to 315°.

Each clamping form 18, 19 further includes an axial circular opening 23in which splines 24 are formed.

These clamping forms 18, 19 are further adapted:

to be moved relative to each other in translation along the bending axis(z) between a spaced-apart position of the junction faces 18 a, 19 a forintroducing and removing a profile and a joined position for bendingsaid profile, andto be driven simultaneously in rotation in the position with thejunction faces 18 a, 19 a joined.

To this end, and firstly, the lower clamping form 19 is fixed in termsof movement in translation along the bending axis (z) and rests on fixedhorizontal friction ring 25.

For its part, the upper clamping form 18 is mobile in terms of movementin translation along the bending axis (z) and to this end is mounted bymeans of a bearing 28 below the lower end of a vertically arranged rod26 a of an actuator 26 the body of which is fastened to a bridge 27extending above the upper table 7 of the first carriage 3, said actuatorbeing adapted:

in its deployed position, to exert a clamping force holding the junctionfaces 18 a, 19 a of the clamping forms 18, 19 joined, andin its retracted position, to hold the two clamping forms 18, 19 intheir spaced-apart position for introducing or removing a profile P orfor changing the bending direction, as described hereinafter.

For their part, the means for driving the two clamping forms 18, 19 inrotation include a vertical shaft 29 that extends along the bending axis(z), is engaged in the openings 23 and has ribs 30 conjugate with thesplines 24, said shaft being driven in rotation by a gearmotor 31 a-31 bcarried by the first carriage 3 between the upper table 7 and ahorizontal lower table 32 of the latter carriage.

Moreover, the rotary shaft 29 is constrained to move in translation withthe vertical rod 33 a of an actuator 33 the body of which is disposed onthe lower table 32 of the first carriage 3, said actuator being adapted:

in its deployed position, to hold the rotary shaft 29 engaged with thetwo clamping forms 18, 19 in each of the relative positions of saidclamping forms, and notably its joined and spaced-apart extremepositions, represented in FIGS. 2 and 3 a, andin its retracted position, and in the spaced-apart position of the twoclamping forms 18, 19, to enable the rotary shaft 29 to be placed in aretracted position in which, as shown in FIG. 3 b, said rotary shaftfrees a space between the two junction faces 18 a, 19 a of said clampingforms adapted to allow the passage of the profile P for changing thebending direction.

According to this principle, the rotary shaft 29 has the function ofindexing the relative position in rotation of the two clamping forms 18,19, at the same time as enabling, in the spaced-apart position of theclamping forms 18, 19, movement of the first carriage 3 along the axis Yfor changing the direction of bending the profile P.

The bending machine represented in FIG. 5 has three clamping forms,adapted not only to enable bending of profiles in two bending directionsbut also to enable bending of two profiles P with different sections.

This bending machine comprises, firstly, a frame 41 including a verticalfront plate 42. This bending machine further comprises a first carriage43 able to slide vertically along a vertical axis Z relative to theframe 41 and consisting of a vertical table 43 having vertical railssuch as 44 adapted to slide in vertical slides such as 45 on the frontplate 42 of the frame 41.

This bending machine also includes a generally stirrup-shaped secondcarriage 46 consisting of:

a vertical table 47 able to slide horizontally along a vertical axis Yrelative to the first carriage 43 and to this end having horizontalslides such as 48 inside which slide horizontal rails such as 49extending along the first carriage 43, anda horizontal upper table 50 on the front portion of which are disposedhorizontal slides such as 54 extending along the axis Y.

This bending machine also comprises a third carriage 51 able to slidehorizontally along the horizontal axis Y relative to the upper table 50of the second carriage 46 and including a horizontal plate 52 on theundersurface of which are provided horizontal rails such as 53 able toslide in slides 54 provided on the upper table 50 of the second carriage46.

This third carriage 51 also includes two parallel vertical plates 55, 56on the horizontal plate 52, each provided toward its upper end with aslide 57 that extends horizontally along an axis X perpendicular to theaxis Y and thus parallel to the axis (x) of movement of the profile P.

Each of these slides 57 is adapted to house a sliding rail 58 forsupporting a guide rule 59, 60, each of said rules including twosuperposed grooves such as 60 a, 60 b with different sections adapted tohouse profiles with different sections.

The tool of this bending machine consists of three clamping forms 62,63, 64 of identical design to the clamping forms 18, 19 describedhereinabove, i.e. clamping forms of which each junction face has tworectilinear grooves with a longitudinal axis perpendicular to thebending radius between which extends a peripheral rebate. These clampingforms consist of:

a clamping form 62 referred to as the intermediate clamping form havingtwo opposite junction faces: an upper junction face 65 a and a lowerjunction face 66 a,a clamping form 63 referred to as the upper clamping form having a lowerjunction face 63 a adapted to cooperate with the upper junction face 65a of the intermediate clamping form 62, anda clamping form 64 referred to as the lower clamping form having anupper junction face 64 a adapted to cooperate with the lower junctionface 66 a of the intermediate clamping form 62.

Moreover, to enable bending of profiles P with different sections, thegrooves such as 67 a, 67 b and the rebates such as 68 a, 68 b formed onthe junction face 63 a of the upper clamping form 63 and the upperjunction face 65 a of the intermediate clamping form 62 have dimensionsdifferent from those of the grooves such as 69 a, 69 b and the rebatessuch as 70 a, 70 b provided in the junction face 64 a of the lowerclamping form 64 and the lower junction face 66 a of the intermediateclamping form 62.

As before, these three clamping forms 62-64 are adapted:

to move in translation relative to each other along the bending axis (z)between a spaced-apart position of the junction faces 63 a-65 a, 64 a-66a for introducing and removing a profile P and a joined position forbending said profile, andto be driven in simultaneous rotation in the position with the junctionfaces 63 a-65 a, 64 a-66 a joined.

To this end, and firstly, the lower clamping form 64 is fixed in termsof movement in translation along the bending axis (z) and rests on afixed horizontal friction ring 71.

Moreover, spring means such as two coil springs 72, 73 are disposedbetween the respective junction faces 63 a-65 a, 64 a-66 a of theclamping forms to spring-load the intermediate clamping form 62 and theupper clamping form 63 toward their spaced-apart position.

The clamping forms 62-64 are held in their joined position by means of avertical shaft 74 that extends along the bending axis (z), is engaged inthe openings 23 provided in said clamping forms and has ribs 75conjugate with the splines 24, said shaft having:

an upper end including a member for limiting movement in translation ofthe upper clamping form 63, consisting in this example of a nut 76,a lower end constrained to move in translation with thevertically-arranged rod 78 a of an actuator 78 the body of which isdisposed on the lower table of a stirrup-shaped part 79 connected to theupper table 50 of the second carriage 46, said actuator being adapted:

-   -   in its deployed position, to allow the intermediate clamping        form 62 and the upper clamping form 63 to be moved toward their        spaced-apart position by the springs 72, 73, and    -   in its retracted position, to exert a clamping force to hold the        junction faces 63 a-65 a, 64 a-66 a of the clamping forms 62-64        joined.

Moreover, this shaft 74 is driven in rotation by a gearmotor 77 a, 77 bcarried by the second carriage 46 under its upper table 50.

According to this principle, the rotary shaft 74 has the functions ofindexing the relative position in rotation of the three clamping forms62-64 and holding said clamping forms in their joined position againstthe action of the spring means 72, 73.

Note further that in this second embodiment the change of bendingdirection is effected by virtue of the facility for movement of the toolrelative to the profile P along the axes Y and Z.

FIG. 8 shows a variant of this second embodiment in which, firstly, thethird carriage 51 carries a single vertical plate 80 the upper end ofwhich forms a horizontal rail 84 extending along the axis X.

Moreover, in this variant the two rules are produced from a singlerectangular parallelepiped-shaped block 81 machined to have:

in planes parallel to the plane (X, Z), two opposite vertical faces 82,83 in each of which are formed two superposed grooves 82 a-82 b, 83 a-83b, respectively, with different sections, adapted to house profiles withdifferent sections, anda lower face in which is produced a slide 85 adapted to house the rail84.

In this variant, the rules 82, 83 are produced in a single block 81carried by a single carriage 80 the movement of which requires only oneguide and only one feed control system, instead of the two guides andthe two control systems required for present-day machines enablingbending in two directions.

It is to be noted that this variant can also be implemented on a bendingmachine conforming to the first embodiment subject to providing thatmachine with means for moving the first carriage 3 along an axis Z.

FIGS. 9 a to 9 d show the operation of a bending machine as representedin FIG. 1 when bending a profile P equipped with a nut E at its end.

Firstly, the angular position of the clamping forms 18, 19 is indexed tomake the axis (x) coincide with the longitudinal axis of the pair ofgrooves appropriate for the selected bending direction, in this examplethe grooves 21 a-21 b (see FIG. 9 a).

Bending is then effected, in conjunction with the corresponding rule 17,by rotating the two clamping forms 18, 19 about the bending axis (z) inthe joined position of said clamping forms (see FIG. 9 b).

As shown in FIGS. 9 c and 9 d, bending in the opposite bending directionis effected in the same manner using the other pair of grooves, in thisexample the grooves 20 a, 20 b, in conjunction with the other rule 16,and, in this example, produces a bending angle greater than 180°.

This illustration highlights one of the essential advantages of thebending machine of the invention, namely the possibility of producingbending angles greater than 180° in both bending directions.

1. Machine for bending a profile (P), including means for holding andmoving (D) the profile along a longitudinal displacement axis (x) and abending head rotatable about a bending axis (z), and further including:at least two clamping forms (18, 19; 62-64) whose axis is the bendingaxis (z), taking the form of discs having plane junction faces (18 a, 19a; 63 a, 64 a, 65 a, 66 a) extending in planes perpendicular to saidbending axis, in which are formed a rectilinear groove (20 a, 20 b; 67a, 67 b, 69 a, 69 b) with a longitudinal axis perpendicular to thebending radius, having an end face (F20) for introduction of a profile(P) and a peripheral rebate (22 a, 22 b; 68 a, 68 b, 70 a, 70 b)profiled in continuity with the introduction face (F20) of said groove,said groove and said rebate being such that, in the joined position ofthe junction faces (18 a, 19 a, 63 a, 64 a, 65 a, 66 a) of two clampingforms (18, 19; 62-64), two joined grooves (20 a-20 b; 67 a-67 b, 69 a-69b) delimit a duct for bending a profile (P) having an end face (F20) forintroducing said profile, and the joined rebates (22 a-22 b; 68 a-68 b,70 a-70 b) define, in continuity with said introduction face, a bendingbearing surface for said profile, means for relative movement intranslation (26; 72, 73, 74, 78) of the clamping forms (18, 19; 62-64)along the bending axis (z), adapted to move them between a spaced-apartposition for introducing and removing a profile (P) and a joinedposition for bending said profile, and rotation drive means (29, 31 a,31 b; 74, 77 a, 77 b) adapted to drive simultaneous rotation of theclamping forms (18, 19; 62-64) in their joined position, said bendingmachine being characterised in that: the clamping forms (18, 19; 62-64)have in each of their junction faces (18 a, 19 a; 63 a, 64 a, 65 a, 66a) a rectilinear second groove (21 a, 21 b; 67 a, 67 b, 69 a, 69 b)forming with the rectilinear first groove (20 a, 20 b; 67 a, 67 b, 69 a,69 b) a pair of grooves delimiting in the joined position of thejunction faces (18 a, 19 a; 63 a, 64, 65 a, 66 a) of the two clampingforms (18, 19; 62-64) two clamping ducts between the introduction faces(F20, F21) of which extends the bending bearing surface for the profiles(P) formed by the two peripheral rebates (22 a, 22 b; 68 a, 68 b, 70 a,70 b) joined, the arrangement of said grooves and rebates being suchthat the bending bearing surface for the profiles delimits between theintroduction faces (F20, F21) of the two clamping ducts a circular arc(α) at least equal to 270° adapted to enable the bending of a length ofprofile (P): either in a first bending direction using one of the twopairs of grooves (20 a, 20 b), by rotation of the clamping forms (18,19; 62-64) in a first rotation direction, or in a second bendingdirection using the other pair of grooves (21 a, 21 b), by rotation ofthe clamping forms (18, 19; 62-64) in a rotation direction that is theopposite of the first rotation direction, means (3, 5, 6; 46, 48, 49)for relative movement of the means (D) for holding the profile (P) andthe bending head are adapted to place the axis of one or the other pairof grooves (20 a-20 b, 21 a-21 b) on the longitudinal axis (x). 2.Bending machine according to claim 1, characterised in that the pair ofgrooves (20 a-21 a 20 b-21 b; 67 a, 67 b, 69 a, 69 b) produced in thejunction face (18 a, 19 a; 63 a, 64 a, 65 a, 66 a) of each clamping form(18, 19; 62-64) is such that the rebate (22 a, 22 b; 68 a, 68 b, 70 a,70 b) produced between the introduction faces (F20, F21) of said groovesdelimits a circular arc (α) between 270° and 315° inclusive.
 3. Bendingmachine according claim 1, including two rules (82, 83) disposed on theupstream side of the clamping forms (62-64) and adapted to enable thebending of a profile (P) by each of the pairs of grooves (67 a, 67 b, 69a, 69 b), characterised in that said rules are mounted on a singlecarriage (51, 80) associated with means (53, 54, 84, 85) for moving saidcarriage.
 4. Bending machine according to claim 1, characterised in thatthe means for driving the clamping forms (18, 19; 62-64) in rotationinclude an axial opening (23) produced in each of said clamping formsand a rotary shaft (29; 74) adapted to extend in these openings (23),said openings and said rotary shaft having conjugate members (24, 30;24, 75) for immobilizing them relative to each other in rotation. 5.Bending machine according to claim 4, including two clamping forms (18,19), characterised in that one of said clamping forms (19), referred toas the fixed form, is fixed in translation along the bending axis (z)and in that the other bending form (18), referred to as the mobile form,is mounted on means for moving said mobile clamping form in translation(26) along the bending axis (z).
 6. Bending machine according to claim5, characterised in that the rotary shaft (29) is carried by means (33)for moving said rotary shaft in translation along the bending axis (z)adapted to enable it to be held engaged with the two clamping forms (18,19) in each of the relative positions of said clamping forms and notablythe joined and spaced-apart extreme positions thereof.
 7. Bendingmachine according to claim 6, characterised in that in the spaced-apartposition of the two clamping forms (18, 19) the means (33) for movingthe rotary shaft (29) in translation along the bending axis (z) enablethe latter shaft to be placed either in a position referred to as thedeployed position in which said rotary shaft is engaged with theclamping forms (18, 19) or in a position referred to as the retractedposition in which said rotary shaft frees, between the two junctionfaces (18 a, 19 a) of said clamping forms, a space adapted to enable thepassage of the profile (P) in order to change the bending direction. 8.Bending machine according to claim 1, characterised in that it includes:three clamping forms (62-64) consisting of: a clamping form (62)referred to as the intermediate clamping form having two opposite upperand lower junction faces (65 a, 66 a), a clamping form (63) referred toas the upper clamping form having a junction face (63 a) adapted tocooperate with the upper junction face (65 a) of the intermediateclamping form (62), and a clamping form (64) referred to as the lowerclamping form having a junction face (64 a) adapted to cooperate withthe lower junction face (66 a) of the intermediate clamping form (62),the grooves (67 a, 67 b) and rebates (68 a, 68 b) produced in the upperclamping form (63) and the upper junction face (65 a) of theintermediate clamping form (62) having dimensions different from thoseof the grooves (69 a, 69 b) and rebates (70 a, 70 b) produced in thelower clamping form (64) and the lower junction face (66 a) of theintermediate clamping form (62) to enable the bending of profiles (P)with different sections, means (43-45) for relative movement of themeans (D) for holding the profile (P) and the bending head adapted toposition said profile facing one or the other pair of clamping forms(62-64).
 9. Bending machine according to claim 8, characterised in that:one of the upper and lower bending forms (64) is fixed in translationalong the bending axis (z), and the rotary shaft (74) is constrained tomove in translation the other of the upper and lower clamping forms (63)and is adapted to bring the three clamping forms (62-64) to their joinedposition against the action of spring means (72, 73) disposed betweenthe respective junction faces of said clamping forms.
 10. Tool forbending a profile about a bending axis (z), including at least twobending forms (18, 19; 62-64) whose axis is the bending axis (z) takingthe form of discs having plane junction faces (18 a, 19 a; 63 a, 64 a,65 a, 66 a) extending in planes perpendicular to said bending axis inwhich are formed a rectilinear groove (20 a, 20 b; 67 a, 67 b, 69 a, 69b) having a longitudinal axis perpendicular to the bending radius and anend face (F20) for introducing a profile (P), a peripheral rebate (22 a,22 b; 68 a, 68 b, 70 a, 70 b) profiled in continuity with theintroduction face (F20) of said groove, said groove and said rebatebeing such that, in the joined position of the junction faces (18 a, 19a; 63 a, 64 a, 65 a, 66 a) of the two clamping forms (18, 19; 62-64),two joined grooves (20 a-20 b; 67 a-67 b, 69 a-69 b) delimit a bendingduct for a profile (P) having an end face (F20) for introducing saidprofile, and the joined rebates (22 a-22 b; 68 a-68 b, 70 a-70 b) definein continuity with said introduction face a winding bearing surface forsaid profile, said tool being characterised in that the clamping forms(18, 19; 62-64) include, formed in each of their junction faces (18 a,19 a; 63 a, 64 a, 65 a, 66 a), a rectilinear second groove (21 a, 21 b;67 a, 67 b, 69 a, 69 b) forming with the rectilinear first groove (20 a,20 b; 67 a, 67 b, 69 a, 69 b) a pair of grooves delimiting in the joinedposition of the junction faces (18 a, 19 a; 63 a, 64 a, 65 a, 66 a) ofthe two clamping forms (18, 19; 62-64) two clamping ducts between theintroduction faces (F20, F21) of which extends the winding bearingsurface for the profiles (P) formed of the two peripheral rebates (22 a,22 b; 68 a, 68 b, 70 a, 70 b) joined, the arrangement of said groovesand rebates being such that the winding bearing surface of the profilesdelimits between the introduction faces (F20, F21) of the two clampingducts a circular arc (α) at least equal to 270° adapted to allow thebending of a length of profile (P): either in a first bending directionusing one of the two pairs of grooves (20 a, 20 b), by rotation of theclamping forms (18, 19; 62-64) in a first direction, or in a secondbending direction using the other pair of grooves (21 a, 21 b), byrotation of the clamping forms (18, 19; 62-64) in a rotation directionthat is the opposite of the first rotation direction.
 11. Bendingmachine according to claim 2, including two rules (82, 83) disposed onthe upstream side of the clamping forms (62-64) and adapted to enablethe bending of a profile (P) by each of the pairs of grooves (67 a, 67b, 69 a, 69 b), characterised in that said rules are mounted on a singlecarriage (51, 80) associated with means (53, 54, 84, 85) for moving saidcarriage.
 12. Bending machine according to claim 2, characterised inthat the means for driving the clamping forms (18, 19; 62-64) inrotation include an axial opening (23) produced in each of said clampingforms and a rotary shaft (29; 74) adapted to extend in these openings(23), said openings and said rotary shaft having conjugate members (24,30; 24, 75) for immobilizing them relative to each other in rotation.13. Bending machine according to claim 3, characterised in that themeans for driving the clamping forms (18, 19; 62-64) in rotation includean axial opening (23) produced in each of said clamping forms and arotary shaft (29; 74) adapted to extend in these openings (23), saidopenings and said rotary shaft having conjugate members (24, 30; 24, 75)for immobilizing them relative to each other in rotation.
 14. Bendingmachine according to claim 2, characterised in that it includes: threeclamping forms (62-64) consisting of: a clamping form (62) referred toas the intermediate clamping form having two opposite upper and lowerjunction faces (65 a, 66 a), a clamping form (63) referred to as theupper clamping form having a junction face (63 a) adapted to cooperatewith the upper junction face (65 a) of the intermediate clamping form(62), and a clamping form (64) referred to as the lower clamping formhaving a junction face (64 a) adapted to cooperate with the lowerjunction face (66 a) of the intermediate clamping form (62), the grooves(67 a, 67 b) and rebates (68 a, 68 b) produced in the upper clampingform (63) and the upper junction face (65 a) of the intermediateclamping form (62) having dimensions different from those of the grooves(69 a, 69 b) and rebates (70 a, 70 b) produced in the lower clampingform (64) and the lower junction face (66 a) of the intermediateclamping form (62) to enable the bending of profiles (P) with differentsections, means (43-45) for relative movement of the means (D) forholding the profile (P) and the bending head adapted to position saidprofile facing one or the other pair of clamping forms (62-64). 15.Bending machine according to claim 3, characterised in that it includes:three clamping forms (62-64) consisting of: a clamping form (62)referred to as the intermediate clamping form having two opposite upperand lower junction faces (65 a, 66 a), a clamping form (63) referred toas the upper clamping form having a junction face (63 a) adapted tocooperate with the upper junction face (65 a) of the intermediateclamping form (62), and a clamping form (64) referred to as the lowerclamping form having a junction face (64 a) adapted to cooperate withthe lower junction face (66 a) of the intermediate clamping form (62),the grooves (67 a, 67 b) and rebates (68 a, 68 b) produced in the upperclamping form (63) and the upper junction face (65 a) of theintermediate clamping form (62) having dimensions different from thoseof the grooves (69 a, 69 b) and rebates (70 a, 70 b) produced in thelower clamping form (64) and the lower junction face (66 a) of theintermediate clamping form (62) to enable the bending of profiles (P)with different sections, means (43-45) for relative movement of themeans (D) for holding the profile (P) and the bending head adapted toposition said profile facing one or the other pair of clamping forms(62-64).
 16. Bending machine according to claim 4, characterised in thatit includes: three clamping forms (62-64) consisting of: a clamping form(62) referred to as the intermediate clamping form having two oppositeupper and lower junction faces (65 a, 66 a), a clamping form (63)referred to as the upper clamping form having a junction face (63 a)adapted to cooperate with the upper junction face (65 a) of theintermediate clamping form (62), and a clamping form (64) referred to asthe lower clamping form having a junction face (64 a) adapted tocooperate with the lower junction face (66 a) of the intermediateclamping form (62), the grooves (67 a, 67 b) and rebates (68 a, 68 b)produced in the upper clamping form (63) and the upper junction face (65a) of the intermediate clamping form (62) having dimensions differentfrom those of the grooves (69 a, 69 b) and rebates (70 a, 70 b) producedin the lower clamping form (64) and the lower junction face (66 a) ofthe intermediate clamping form (62) to enable the bending of profiles(P) with different sections, means (43-45) for relative movement of themeans (D) for holding the profile (P) and the bending head adapted toposition said profile facing one or the other pair of clamping forms(62-64).